When Roger Penske returned to NASCAR in 1991, he entered with a proven champion in Rusty Wallace.

He had dabbled in stock cars for about a decade and then abandoned those efforts while enjoying success with Indy cars. Finally, he was ready to get back to racing stock cars, and he figured he had the right guy to win championships.

They flirted with titles early, finishing second in the standings in just their third year together and third the following season.

But Penske has never enjoyed the ultimate success. Yes, he’s won the Daytona 500 (in 2008 with Ryan Newman). But he hasn’t won a Sprint Cup Series championship. Wallace never delivered, and neither did Kurt Busch or Newman.

Penske’s quest for his first Cup title could very well end this weekend, as Brad Keselowski sits 20 points ahead of Jimmie Johnson with just the season finale at Homestead-Miami Speedway remaining.

It’s been 22 years of near-misses and big misses.

“We haven’t been good enough,” Penske said last Sunday prior to the race at Phoenix. “Quite honestly, we haven’t been able to deliver. When you don’t win, that’s what it’s all about. It’s about the team. It’s about the driver. We just need to get our game better and more consistent.”

Penske knows what it’s like to win championships. He’s won 23 national racing titles, including 12 in IndyCar.

“We’ve been good in the past but we’ve never been able to close the deal.”

But now he’s got Keselowski, a 28-year-old driver in just his third year of full-time Cup racing, set to close the deal. All Keselowski needs to do is finish 15th or better this weekend at Homestead and Penske will get a seat on stage at the postseason awards banquet.

“It’s just not something that you can answer in a setting like this and really give someone the sound byte they’re looking for because it’s so much bigger than that,” Keselowski said earlier this month.

“It’s basically the culmination of a life’s worth of work, and not just one, but three or four or even more than that when you count in my crew chief and mechanics, family, car owner, and so forth. The best way that I can probably answer it is that it’s a culmination of several lives’ worth of work.”

Penske drivers have won 73 Cup races, and five of those have come this year from Keselowski, who also has 13 top fives and 23 top 10s in 35 events.

It’s not just the ability to win races but the ability to string together solid finishes that might bring Penske the title.

“In this business, you’ve got to be consistent,” Penske said. “It’s not about winning every race. It’s about the top fives and top 10s that make a difference. That’s one of the things that I think we have done a better job this year when you look at the consistency of the 2 car.”

Penske hired the at-times overly-aggressive-yet-successful Keselowski after the driver showed promise with six wins in the Nationwide Series as well as a Cup win at Talladega in 2009 for car owner James Finch.

Keselowski promptly gave Penske his first title in any NASCAR division as he won the Nationwide championship in 2010.

The next year, Keselowski made the Chase for the Sprint Cup and turned a three-win season into a fifth-place finish in the standings, setting up this year’s run for a title.

“The cream has come to the top,” Penske said. “He was controversial when he first came with us three years ago. But if anything comes out of this season, the respect that Brad Keselowski has in the garage now is one of the best in the business.”

Winning a championship would rank among one of his many top racing accomplishments, Penske said.

“You look at the things you’ve won in the past and we’ve never been there,” Penske said. “We’ve been close. We finished second in ’93 and third in ’94 (with Wallace). This would be right at the top because the competition is so tough.

“Thirty-eight weekends, so many things can happen. We have some real depth in our organization now to keep us competitive in the future.”

Penske admitted it’s nerve-wracking.

“I try to be cool and calm all the time,” Penske said. “Maybe I am outside but inside, obviously, you’ve got a lot of butterflies. … Anything can happen.”